Fixed multiple issues with showing correct selection in navigator and
3d edit view:
- Dragging items from item library selects only that item,
regardless if drag was done to 3d edit view or navigator
- Selection is shown correctly after reparenting items, including
multiselection reparenting
- Adding a new item to the active scene now shows selection box
correctly for that item
Change-Id: I5156ca4c22e606c41e1e346ea5c32c3d70d89f5e
Fixes: QDS-1577
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>